Good park up for vans at the end of the road to the island. You can overnight here with no hassle.
Site is about 20 minutes walk from the parking along the fantastic 'tombolo' beach and onto the island, though you are likely to take longer as you get distracted by seals, birds and the overall beauty.
Oddly the section of the chapel where a section of ground has been cut away to show the original floor level has become a depository for 'votive' coins.
In 1958 a schoolboy helping to excavate the site struck upon a hoard of silver ornaments believed to have been hidden from Viking invaders. This treasure believed to be pictish in origin can now be seen at the Scottish Museum in Edinburgh.
The site of St Ninian's Chapel was in use during the Iron Age period. Here's what CANMORE has to say about it...
The site was recovered by excavation by Prof. O'Dell between 1955 and 1959, revealing the foundations of a 12th century church, overlying a pre-Norse(?) church, which in turn overlay an Iron Age site (possibly a wheel house) yielding pottery datable to about the 2nd century AD. Each level was accompanied by contemporary graves, those of the Iron Age being centred on a crouched burial of late Bronze Age type, which lay SW of the chancel of the medieval church.